1. Field of the Invention
This invention relates to apparatus for charging a shaft furnace for burning carbonaceous mineral material in at least two furnace shafts, which charging apparatus comprises a common feed container, which is connected to each furnace shaft by a separate charging duct.
2. Description of the Prior Art
Austrian Patent Specification No. 377,078 discloses a known apparatus which is of the kind described hereinbefore and which comprises charging pipes leading from the common feed container to the furnace shafts, which are adapted to be charged in alternation with the feed material, which is fed from the feed container to each furnace shaft which is to be charged. A batching device is associated with that container and ensures that each furnace shaft will be charged with a predetermined quantity of feed material so that in comparison to charging apparatus having a separate feed container for each furnace shaft that known apparatus has the advantage that a charging of equal quantities of the feed material to all furnace shafts can be ensured in a simple manner because a variation of the batches by different batching devices associated with respective furnace shafts need not be feared. Besides, the structural expenditure may be relatively low. But said advantages are offset in part by the disadvantage which resides in that pressure lock chambers must be provided between the common feed container and the respective furnace shafts because each furnace shaft must be gastightly sealed. Said lock chambers will add to the required overall height. The pressure lock chambers may comprise a flap valve for each furnace shaft and bell valves succeeding said flap valves. When such charging apparatus is to be used to charge a given furnace shaft, the flap valve associated with that shaft must be opened so that the batch of material that has been delivered to the feed container is transferred through the associated charging pipe to the space which is disposed in the furnace shaft between the flap valve and the bell valve. Thereafter the flap valve is closed and the bell valve can subsequently be opened. Because the feed material rests on the valve bell of the bell valve, the sealing surface of that valve is contacted by the feed material so that undesired loads will be applied.